Roguelikes are usually made to be quite portable. Either if they use Curses (Ncurses on all unices, PDCurses on Windows) or tiles (SDL is used, which is avaliable on almost every platform) or even 3D (OpenGL is avaliable pretty everywhere).

There's a new trend to develop for Java virtual machine, that way, your game will run on most platforms, but be warned: the experience isn't always first-class, and sometimes user will need to install the JVM in order to play. Sometimes, specific Java libraries for drawing or sound used, some of which require additional native libs, thus effectively defeating the cross-platformness.